1. Field of the Invention
The present invention relates to a data driver and a display apparatus, In particular, the present invention relates to a data driver capable of providing a desired image on a display panel and a display apparatus having the data driver.
2. Description of the Related Art
Typically, a liquid crystal display (LCD) includes a liquid crystal display panel that displays an image. LCDs are classified into polysilicon type LCDs and amorphous silicon type LCDs.
In a polysilicon type LCD, a gate driver, which applies a gate signal to the liquid crystal display panel, and a data driver, which applies a gamma voltage to the liquid crystal display panel, are integrated on the liquid crystal display panel through a thin film process. In addition, various parts, such as a timing controller, a gamma voltage generator, etc., are further integrated on the liquid crystal display panel.
The data driver includes a shift register, a latch, a converter, and an output buffer. The converter receives a plurality of gamma voltages from the gamma voltage generator. The converter selects a gamma voltage among the plurality of gamma voltages at the trigger of a data signal from the timing controller, and outputs the selected gamma voltage.
In the converter, gamma voltage lines cross data signal lines. Consequently, unwanted coupling between them changes the gamma voltage along with the change of the logic state of the data signal. As a result, the converter can not output the correct gamma voltage, and the liquid crystal display panel can not display the images faithful to the desired gray scales.